Driving mechanism



Dec. 14, 1943. R, M, NARDONE v 2,336,562

DRIVING MECHANISM Filed Nov. 15, 1941 INVENTOR, Panza M. Ngomvz: BY

fiTTflR/VEX Patented Dec. 14, 1943 UNITED STATES PATENT OFFICE DRIVING MECHANISM Romeo M. Nardone, Westwood, N. J., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 15, 1941, Serial No. 419,341 2 Claims. (01. 172-239) and particularly to driving mechanism of the pended claims for this purpose. type which includes a yieldable clutch means In the drawing, enabling the motor to overrun the driven element Fig. 1 is a longitudinal sectional view of a deas soon as the latter reaches the limit 'of its vice to which the invention may be applied, (the travel. This is of special importance in the selected device Eorresponding to that of Allen actuation of aircraft landing gear, the improve- Patent No. 2,184,032); and ment of which constitutes a major object of the Fig. 2 is a schemat c diagram of the preferred present invention. embodiment.

One of the requirements in airplane installa- Reference characters 5 and 6 designate driving tions is that the friction clutch must be capable shafts mounted at right angles to one another of slipping for five minutes at its normal clutch -in a common housing 1, either of the shafts be-- setting without any increase in clutch value. ing capable, under certain conditions, of actuat- This is claimed to be necessary in case the limit ing a driven shaft 8 also journalled in an extenswitches on the part moved; suchas the landing l5 sion 9 of the housing 1, a similar extension II gear, fail to function. In that case the motor being provided as a means of housing a motor will keep on operating and the clutch will slip or other actuating means for the shaft 5. until the pilot manually shuts on the motor. The elements involved in the choice of driving Since the airplane structure must be made as means for the driven shaft 8 (which may be the light in weight as it is possible to make it, any actuator of a landing gear such as that of the increase in clutch value brought about by the Minshall Patent No. 2,005,980 of June 25, 1935, heat created in the plates would be dangerous or some other load to be driven) include a soleto the structure. It is well known that the usual noid I3 and a bevel gear l4 herein shown as intype of pre-set friction disc clutch has a marked tegral with the enlarged and centrally bored end tendency to rise in torque value when slipping I5 of the driven shaft 8 and so located with refor a number of seconds. There are, of course, Speet t0 the driving shafts 5. and 6 that it is special'clutchmechanisms that will not rise in capable of receiving rotation from either of said torque value but these would be complicated and Shafts depending up n W e it is n a e theavy. hand position as shown in Fig. 1, or its right- If the electric motor of the power unit could hand position (not shown). In the former posibe automatically cut out after only one or two tion the clutch teeth l1 which are formed upon seconds of clutch slippage (in case the limit th h l ow nd of th shaf l5 are fully enga ed switch did not function) the five minute requirewith the correspondingly shaped teeth I8 on the ment would notbenecessary, nor would any difilo sp y bo end of t Shaft While culty be experienced with rise in clutch torque. in the latter position the teeth I! and 18 are dis- To provide such automatic cut-out action is an en a d. but th te th f bev l a I 4 ar u y object of thi i v nti meshed with those of the correspondingly shaped Another object is to reduce installation weight. bevel pinion Shown herein as n inte ra X- To thisend, t is proposed to provide a reversible tension of the driving shaft 6, the outer end of motor having only one set of field coils and which is provided with a pin 23 or other suitable rent reversing means including two small solemeans Serving for t hm of a sleeve 24 or noids to actuate two sets of commutator brushes other mafluauy f nl zt lillnegtality. A Cfll to engage one or the other set with the commucompresslon sprmg 2 cons an y ears aga'ms tator, according to the desired direction of rotacollar- 28 held fast to the inner end of shaft 5 by tion.1t An appreciable weight saving will thereby $222322 gg i fi g g g i i igg gg gg fg g g z resu teetn Hi from the teeth ll of the shaft 8. S rin These and other objeFts of mventlon Wm 21 therefore opposes the pull of the soleno d I? become apparent from inspection of the followand the latter when energized t upon th in specifica ion w r ad wi reference to the shaft 5 which constitutes a movable magnetiza compan in drawin wher in is illus r d t able core with respect to the winding l3, a sleeve preferred embodiment of the invention. It is to 3| oi non-magnetizable material being wrapped be expressly understood, however, that the drawabout that portion of the core 5 which is on the ing is forthe purpose of illustration only, and left of the center line of the coil l3 so that the is not designed as a definition of the limits of effect of the magnetic flux resulting from ener- This invention relates to driving mechanism, the invention, reference being had to the apgizationof the coil l3 extended position.

is to draw the shaft to the left, the gear l4 moving with the said shaft 5 by reason of the interlocking projections 33 and 34 formed upon the shaft 5 and the gear l4, respectively. Upon deenergization of the solenoid l3 these interlocking larly effective to draw the gear I4 into mesh with the gear 2| in response to the thrust exerted by the expansion of the spring 21 from its fully compressed position, as shown in Fig. 1, to its The left-hand end of the spring 21 rests against collar or disc 4| which engages the shoulder 42 of the relatively stationary sleeve 43 constituting the inner race of a friction disc clutch 44 consisting of a plurality of interleaving friction plates splined alternately to the sleeve 43 and a second sleeve or shell 46 hav-'- to a driving an inwardly turned rim 41 secured ing member 48 by a suitable means such as that indicated at 49, the said driving means 48 being a part integral with or connecting to the armature of the electric motor indicated diagrammatically at H in Fig. 2. Transmission of torque from the clutch elements 46, 44, 43 to the shaft 5 is provided for in the form of splines 53 on the shaft 5 engaging corresponding splines on the inner surface of the sleeve 53, the outer surface thereof being threaded to receive a nut 56 which constitutes a means for adjusting the pressure of springs 5e and hence the torque transmitting capacity of the clutch 44.

The solenoid winding as is shown in 2 as connected in a circuit 86 leading from manual switch 51 to a battery 69 constituting the source of current for the electric motor iii. The motor commutator M (Fig. 2) is preferably provided with four brushes (16, ii, l8, l9) and the field windings It are in series therewith. A pair-of solenoids 8i and 82 are provided, one of which acts upon brushes l6 and ii to engage them with the commutator and thus cause clockwise rotation of the motor in one position of switch 617, and the other of which solenoids is energized to engage brushes l8 and i9 and thereby produce counterclockwise rotation or" the motor in the opposite position of the switch 5?, said solenoids being connected with the source 69, as indicated at 83 and 84; and the brush operating structure being preferably like that shown in Figs. 5 and 6 of my application No. 387,540, filed April 8, 1941.

Thenovel automatic motor deenergizing (cutout) means will now he described:

In the line between battery and motor, as illustrated at 81, there is included a thermostatic, snap-action switch 88 which remains closed under normal operation of the unit but which will over-heat under and therefore snap open. 44 is usually set about 50% The slipping clutch higher than the norprojections are simi- Y slipping clutch torque load assaoea mal torque required during operation. Therefore, under normal con 'tions the current flow through the thermo-switch will be fairly low. when the clutch 44 slips, the motor will draw an 5 appreciably higher current, and this increased current flow occurs through the switch. It requires only a few seconds of this increased cur- .rent flow to produce a suflicient heat rise to cause the switch 88 to snap to the open position. The 10 motor then stops.

After such automatic breaking of the motor circuit, the operator may open switch 61 manually; but if the operator fails to open this manual switch 6?, the subsequent automatic reclosing of the thermo-switch (upon cooling) will start the motor again. The cycle of opening and clos-' i m y, adjustments to the thermo-switch may be made so as to delay the reclosing for a considerable length of time.

What is claimed is:

1. Motor control means comprising, in combination with the main motor winding, energizing means including a source of current and a circuit from said source to said main winding, said circuit including normally disengaged commutator brushes and a normally closed switch, means responsive to development of a predetermined current value in said main winding to open said normally closed switch, whether the motor temperature be high or low when said predetermined current valueis reached, a pair of brusheng'aging solenoids in parallel circuit relationship to said main winding, and means for selectively energizing said solenoids, to cause current flow through said main winding, and hence the rotation of said motor, in one direction or the other, according to which solenoid is energized, said means further operating to continue such rotation until operation of said switch-opening means.

2. Motor control means comprising, in combi-' nation with the main motor winding, energizing means including a source of current and a circuit from said source to said main winding. said circuit including normally disengaged commutator brushes and a normally closed switch, means responsive to development of a predetermined currentvalue in said main winding to open said normally closed switch, a brush-engaging solenoid in parallel circuit relationship to said main winding, and means for energizing said solenoid, to cause current flow through said main winding, and hence the rotation of said motor, said means further operating to continue such rotation until operation of said switchopening means.

ROIWEO M. NARDONE.

in fact, recur several times, but suitable 

